[U-Boot] Dynamically define which Kernel image to boot during SPL execution

[U-Boot] Dynamically define which Kernel image to boot during SPL execution

[0xbin4ry]

Hi there,

I want to chose from two different Android kernel images to be booted
during SPL execution. Thus, I guess I need to a) pass u-boot.img two
different parameters or b) call two different u-boot.img files, which in
turn call the corresponding kernel images?

Thanks in advance,
-b

[U-Boot] Dynamically define which Kernel image to boot during SPL execution

[Wolfgang Denk]

Dear 0xbin4ry,

don't you have a real name?

In message <52518C7E.3010704@gmail.com> you wrote:
> 
> I want to chose from two different Android kernel images to be booted
> during SPL execution. Thus, I guess I need to a) pass u-boot.img two

What would "u-boot.img" be here - the full U-Boot image loaded by the
SPL?  If you load and start that, then this would be the place where
you determine which kernel image to load and start.  However, if
you're uysing Falcon mode, then you would not load any u-boot.img at
all, and the SPL would include the code to determine which kernel
image to load and start.

> different parameters or b) call two different u-boot.img files, which in
> turn call the corresponding kernel images?

No, this would never be the case.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
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[U-Boot] Dynamically define which Kernel image to boot during SPL execution

[bin4ry]

Am 06.10.2013 21:31, schrieb Wolfgang Denk:
> Dear 0xbin4ry,
>
> don't you have a real name?
Yes indeed, Peter.
> What would "u-boot.img" be here - the full U-Boot image loaded by the
> SPL?  If you load and start that, then this would be the place where
> you determine which kernel image to load and start.
The only code I found in the SPL regarding the call of u-boot.img were
the following functions:

mmc_load_image_fat() -> file_fat_read() -> do_fat_read() [here, the
u-boot.img file is copied to DDR memory] -> jump_to_image_no_args()
[here, we excute the u-boot.img code].

However, I could not find any signs of any boot parameters (except for
CONFIG_EXTRA_ENV_SETTINGS in omap4_common.) but I could not figure how
to dynamically alter these parameters.
>   However, if
> you're uysing Falcon mode, then you would not load any u-boot.img at
> all, and the SPL would include the code to determine which kernel
> image to load and start.
I guess I have to read about falcon mode. Did not know about this before.

Basically, I want to determine which Android kernel to boot based upon a
calculation executed by the SPL. Maybe you know if more elegant ways
then the ones I am thinking of.

A little bit off-topic, however it could help my in this scenario
anyways: Is it possible to show a splash screen in the SPL or the loaded
u-boot.img on an OMAP4460? I browsed the web and found several
statements that this is not supported. However, these statements seemed
to be rather vague..

Best regards,
Peter